The present invention relates to an image forming apparatus, a developer supply method for the apparatus and an image processing board, and more particularly, to a developer supply method in an image forming apparatus which forms an image in accordance with an electrophotographic method.
In recent years, computers in respective places of the world are linked via the Internet, and various information searches and browsing are made by utilizing the network. Generally, a computer holding a software program specialized for browsing information (hereinafter referred to as a xe2x80x9cbrowserxe2x80x9d) is connected to a server linked to WWW (World Wide Web) via the network, and information on the WWW server is referred to in accordance with HTTP (Hyper Text Transfer Protocol) protocol from the computer.
Further, this browser can download the browsed information on the WWW server to the computer and stores the information there. As the information stored in the computer can be outputted to an image output apparatus having a printing function and print-outputted from the image output apparatus in accordance with necessity, various information on the WWW server can be stored in a recording medium or print-outputted.
Generally, a laser-beam printer which forms an image in accordance with an electrophotographic method or an ink-jet printer which performs image printing in accordance with an ink-jet method are used as the image output apparatus. These printers performs image processing on image data transmitted from a connected host device such as a computer to convert the data to data of appropriate format to the printer.
However, in the conventional printers, as fixed image processing is always performed regardless of image data type or contents, the following problems occur.
In image data of photograph or the like, tonality is important, while image data of illustration or the like, resolution is important. In the conventional art, the same image processing is performed on all the image data, therefore, in some cases, the tonality of image data of photograph or the like is impaired or the resolution of image data of illustration or the like is damaged.
It is difficult to output data with optimum color tone corresponding to each image data since fixed gamma conversion processing is performed. Similarly, it is difficult to output data with optimum color tone corresponding to each image data since the same under color processing is performed.
To solve this problem, Japanese Published Unexamined Patent Application No. 2000-207164 discloses an image processing apparatus which performs image formation based on image data obtained from a network. In the apparatus, it is determined whether the image is a tonality-oriented image or a resolution-oriented image from the extension of image file, and image processing corresponding to the type of image data is performed.
Further, an image formation apparatus such as an electrophotographic-type digital copying apparatus is often used. This apparatus converts an original image by a reading device and obtains a printed image. In this image forming apparatus, image data transmitted from a computer is transferred to the image forming apparatus via an external apparatus.
The external apparatus, which accesses the network to obtain image data, converts the obtained image file into a raster image, and performs image processing to obtain an appropriate printed image, has a large scale hardware since it includes various processing circuits. However, in recent years, the hardware circuits are highly integrated, and in some cases, such external apparatus is incorporated in the image forming apparatus.
Further, it is recently necessary for the above-described printer apparatus as a computer peripheral device to have product specifications to selectively hold various image processing boards in accordance with a user""s preferences and to attain user""s desired cost and functions. That is, a part or all of image processing circuits must be exchangeable.
In this manner, designing for flexible arrangement of image processing circuits is required in the image output apparatus. On the other hand, image processing methods are increasingly progressed, and various image processings are proposed corresponding to various image data characteristics by original images and characters. Further, an arrangement to perform appropriate image processing automatically or in correspondence with a user""s designation has been proposed. In this case, it is difficult to independently perform processing on the image processing circuit side and processing on the printer engine side.
For example, in an image forming apparatus having a function of predicting the amount of consumption of toner (developer) in correspondence with image data and performing toner density control, image processing closely related to printer control such as gamma conversion is performed on the printer engine side. That is, as part of control of image formation means of image forming apparatus, image processing corresponding to engine characteristic is performed on the printer engine side and the engine characteristic is corrected. The printer engine receives image data, performs integration processing on the image data, predicts the amount of toner consumption from the result of integration, and controls toner supply to a developer unit.
Further proposed is an image forming apparatus which forms a toner patch image on an electrostatic drum, measures toner density in the developer unit, and controls toner supply with high precision from the result of integration of image data and toner density information in the developer unit.
On the contrary, a low-cost printer engine has been provided by omitting primary image processing functions on the printer engine side of image forming apparatus upon constructing a high-level and large-scale image processing circuit and providing an image processing board instead of the primary image processing.
In this manner, if the construction of image processing circuit of image forming apparatus is reviewed in more detail, it is understood that to provide various image processing functions with a flexible construction of image processing circuit, it is desirable to handle necessary information not on the printer engine side but on the image processing board side.
However, as described above, in the conventional image forming apparatuses, necessary information is handled almost on the printer engine side regarding toner supply control which is closely related to the printer characteristic.
Accordingly, in a case various image processings are to be performed, it is difficult to integrate primary image processing functions on the image processing board.
Accordingly, the first object of the present invention is to provide an image forming apparatus which performs appropriate toner supply control by predicting the amount of toner consumption based on image data even in a flexibly-constructed image processing board for various image processings is used in the image forming apparatus.
The second object of the present invention is to provide a developer supply method for an image forming apparatus by predicting the amount of toner consumption based on image data even in a flexibly-constructed image processing board for various image processings is used in the image forming apparatus.
The third object of the present invention is to provide an image processing board having a flexible construction for various image processings, which integrates respective data values of processed image data and outputs the integrated value.
According to one aspect of the present invention, the foregoing first object is attained by providing an image forming apparatus which forms an image in accordance with an electrophotographic method, comprising: storage means for storing image data; image processing means for performing image processing on the image data stored in the storage means; and image formation means for forming an image using developer based on the image data processed by the image processing means, wherein the image processing means includes developer consumption amount calculation means for generating information on a predicted amount of the developer consumed by the image formation means, based on the image data processed by the image processing means, and wherein the image formation means supplies the developer in correspondence with the information generated by the developer consumption amount calculation means.
According to the image forming apparatus of the present invention, image data is stored in the storage means, and the image processing means performs image processing on the image data stored in the storage means and generates information on the amount of developer as a predicted amount of developer consumed upon image formation, and the image formation means forms an image by using the developer based on the image-processed image data, and supplies the developer in correspondence with the information on the predicted developer consumption amount.
In this manner, as primary image processing functions can be integrated on an image processing board as the image processing means, even in a case a flexibly-constructed image processing board for various image processings is used in the image forming apparatus, the amount of consumption of developer is predicted based on image data and appropriate developer supply control can be performed.
Note that it is desirable that the image processing means changes the image processing on the image data based on whether the image data represents a tonality-oriented image or a resolution-oriented image, and wherein the developer consumption amount calculation means corrects the information in correspondence with executed image processing.
In this case, it is preferable that the image processing means determines whether the image data represents a tonality-oriented image or a resolution-oriented image based on an extension included in a file name of the image data.
Further, it may be arranged such that the image forming apparatus is connected to a network, and the apparatus further comprises: input means for inputting information on the image data; and issuance means for issuing an image request to the network based on the information inputted by the input means, and the storage means holds image data transmitted in response to the image request by the issuance means.
Further, it is preferable that the image forming apparatus further comprises reading means for reading an original image and generating image data, and the storage means holds the image data generated by the reading means.
According to another aspect of the present invention, the foregoing second object is attained by providing a developer supply method for the image forming apparatus, wherein at the image processing step, the image processing on the image data is changed based on whether the image data represents a tonality-oriented image or a resolution-oriented image, and wherein at the developer consumption amount calculation step, the information is corrected in correspondence with executed image processing.
The above second object is also attained by providing a computer program including program code corresponding to the respective steps of the above developer supply method for image forming apparatus, and a storage medium holding the computer program.
According to another aspect of the present invention, the foregoing third object is attained by providing an image processing board of an image forming apparatus which forms an image in accordance with an electrophotographic method, comprising: an image processing circuit that performs image processing on input image data by using a parameter designated from pre-set plural parameters; and an integration circuit that integrates each data value upon output of the image data resulted from to the image processing.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same name or similar parts throughout the figures thereof.